The present invention relates to an anti-vibration supporting structure for an outboard engine system in which a swivel shaft is laterally swingably supported on a bracket device fixed to a hull, and an outboard engine system body is supported in an anti-vibration manner on the swivel shaft with an elastic rubber interposed therebetween.
In general, an outboard engine system includes an engine room in which an engine is accommodated, and a case body extending downwards from the engine room to accommodate a drive shaft driven by the engine. The engine room and the case body are supported on a hull by an anti-vibration supporting device using an elastic rubber.
More specifically, there is employed an anti-vibration supporting device having a structure in which outer and inner peripheral surfaces of a pair of cylindrical rigid members disposed coaxially with each other are coupled to each other by elastic rubbers, or a pair of plate-shaped rigid members disposed in an opposed relation to each other are coupled to each other by elastic rubbers, thereby constituting an anti-vibration assembly, wherein inner one of the cylindrical rigid members or one of the plate-shaped rigid members is mounted to a bolt extending in an arm-shape from each frame mounted at an upper and lower locations on a swivel shaft. There is also employed another anti-vibration supporting device having a structure in which an anti-vibration assembly is formed as a single component comprising an interior rigid member (a core metal) and elastic rubbers surrounding a periphery of the interior rigid member, wherein the interior rigid member is fixed to a bolt extending in an arm-shape from each frame mounted at an upper and lower vertical locations on a swivel shaft, and the elastic rubbers are restrained in an engine room or a recess defined in a case body.
However, any of the anti-vibration supporting device suffers from the following problem: The elastic rubber supported on the upper rigid member is disposed in the vicinity of an upper end of the swivel shaft, and the elastic rubber supported on the lower rigid member is disposed in the vicinity of a lower end of the swivel shaft. For this reason, in order to increase the distance between the upper and lower elastic rubbers to enhance the anti-vibration effect, it is necessary to increase the length of the swivel shaft, resulting in increases in weight and cost.
In addition, any of the anti-vibration supporting device also suffers from a problem that a component or a structure (a nut threadedly fitted over the bolt, or a working space for operating the nut) is required for fixing the rigid members of the anti-vibration assembly to the bolt extending from the frame and hence, the anti-vibration supporting device is correspondingly complicated and increased in size, and the cost is increased.
The present invention has been accomplished with such circumstances in view, and it is a first object of the present invention to ensure that the distance between the upper and lower elastic rubbers on the swivel shaft is increased without extension of the length of the swivel shaft itself of the outboard engine system, thereby enhancing the anti-vibration effect.
It is a second object of the present invention to provide an anti-vibration supporting structure for an outboard engine system, which is simple in structure, small-sized and inexpensive in cost.
To achieve the first object, according to a first aspect and feature of the present invention, there is provided an anti-vibration supporting structure for an outboard engine system in which a swivel shaft is laterally swingably supported on a bracket device fixed to a hull, and an outboard engine system body is supported in an anti-vibration manner on an upper rigid member coupled to an upper end of the swivel shaft and a lower rigid member coupled to a lower end of the swivel shaft with elastic rubbers interposed therebetween, respectively, characterized in that the lower rigid member includes a swivel shaft extension extending downwards from the lower end of the swivel shaft, and elastic rubber support portions extending laterally from the lower end of the swivel shaft extension for supporting the elastic rubbers.
With the above arrangement, the outboard engine system body is supported at its lower portion in the anti-vibration manner by the lower rigid member having the elastic rubber support portion provided at the lower end of the swivel shaft extension extending downwards from the lower end of the swivel shaft. Therefore, the distance between the upper and lower elastic rubbers can be increased without downward extension of the swivel shaft itself to enhance the anti-vibration effect, while avoiding an increase in extra weight and an increase in cost. In addition, the elastic rubbers are supported on the elastic rubber support portions extending laterally from the lower end of the swivel shaft extension. Therefore, the distance between the left and right elastic rubbers can be decreased without interference with the swivel shaft to avoid a reduction in anti-vibration effect.
An oil case 41 and an extension case 42 in embodiments correspond to an outboard engine system body of the present invention. A mounting bracket 55 in the embodiments corresponds to the bracket device of the present invention, and a mount frame 63 in the embodiments corresponds to the upper rigid member of the present invention. A center frame 64 in the embodiments corresponds to the lower rigid member of the present invention, and a core metal 642 in the embodiments corresponds to the elastic rubber support portion of the present invention. An upper mount rubber 74 and a lower mount rubber 80 in the embodiments correspond to the elastic rubbers of the present invention.
To achieve the second object, according to the present invention, there is provided an anti-vibration supporting structure for an outboard engine system in which a swivel shaft is laterally swingably supported on a bracket device fixed to a hull, and an outboard engine system body is supported in an anti-vibration manner on the swivel shaft with elastic rubbers interposed therebetween, characterized in that the elastic rubbers are integrally provided around tip ends of the rigid member extending laterally from the swivel shaft, and are restrained in elastic rubber restraining portions provided in the outboard engine system body.
With the above arrangement, the elastic rubbers integrally provided around the tip ends of the rigid member extending laterally from the swivel shaft are restrained in elastic rubber restraining portions provided in the outboard engine system body and hence, a component or a working space for fixing the elastic rubbers to the rigid member is not required, whereby the structure of the anti-vibration supporting device for the outboard engine system can be simplified, contributing to reductions in size and cost.
An extension case 42 in the embodiments corresponds to the outboard engine system body of the present invention, and a rubber accommodating portion 422 and a cover member 81 in the embodiments correspond to the elastic rubber restraining portion of the present invention. A center frame 64 in the embodiments corresponds to the rigid member of the present invention, and a lower mount rubber 80 in the embodiments corresponds to the elastic rubber of the present invention.